In a wireless communication system supposing a high-speed movement such as an LTE (long term evolution) system, receiving characteristics are ensured by enhancing the accuracy of channel estimation with use of pilot symbols. Furthermore, in this type of systems, transmission technology using a plurality of antennas, for example, transmission technology represented by MIMO (multiple input multiple output), is used in order to provide high-speed communication. Pilot symbols are assigned to each of the antennas.
Meanwhile, a method of obtaining an error in the time direction and an error in the frequency direction and comparing them with each other to select an interpolation method (hereinafter referred to as “determination of a direction of estimation of virtual generated values”) has been known as one of channel estimation techniques. This method employs the following characteristics: When a movement speed is fast, an error of an interpolation in the time direction increases. When a delay dispersion is large, an error of an interpolation in the frequency direction increases.
Some conventional technologies include a propagation path transfer function estimator that estimates a transfer function matrix of a propagation path based upon a received signal and an interference remover-decoder that removes interference of the received signal and decodes transmission data based upon the received signal and the transfer function matrix (see, e.g., Patent Literature 1). In this case, the interference remover-decoder performs a decoding operation with a conjugate gradient method so as to decode transmission data based upon the received signal and the transfer function matrix.